Fix bugtracker #95: collections pane shows "Untitled project" for a titleless project

The root of a project's embedded collection showed "Projet sans titre"
whenever the project had no title, while the project panel shows the
file name. Fall back to the file name the same way, and only use
"Projet sans titre" for a project that has neither.

The name was also computed once, so changing the project title or saving
it under a new name left the pane stale until the collections were
reloaded. Update it on projectTitleChanged and projectFilePathChanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

sources/ElementsCollection/xmlprojectelementcollectionitem.cpp

@@ -21,6 +21,8 @@
 #include "../qetproject.h"
 #include "xmlelementcollection.h"
 
+#include <QFileInfo>
+
 /**
 	@brief XmlProjectElementCollectionItem::XmlProjectElementCollectionItem
 	Constructor
@@ -58,10 +60,7 @@ QString XmlProjectElementCollectionItem::localName()
 		return text();
 
 	if (isCollectionRoot()) {
-		if (m_project->title().isEmpty())
-			setText(QObject::tr("Projet sans titre"));
-		else
-			setText(m_project->title());
+		updateProjectName();
 	}
 	else {
 		ElementsLocation location (embeddedPath(), m_project);
@@ -71,6 +70,25 @@ QString XmlProjectElementCollectionItem::localName()
 	return text();
 }
 
+/**
+	@brief XmlProjectElementCollectionItem::updateProjectName
+	Set the displayed name of the collection root from the project :
+	its title, or its file name when it has no title, like the project panel.
+	Does nothing if this item is not the root of the collection.
+*/
+void XmlProjectElementCollectionItem::updateProjectName()
+{
+	if (!isCollectionRoot() || !m_project)
+		return;
+
+	if (!m_project->title().isEmpty())
+		setText(m_project->title());
+	else if (!m_project->filePath().isEmpty())
+		setText(QFileInfo(m_project->filePath()).completeBaseName());
+	else
+		setText(QObject::tr("Projet sans titre"));
+}
+
 /**
 	@brief XmlProjectElementCollectionItem::name
 	@return The collection name of this item